External pipe and tube coating apparatus



March 196 8 J. w. WEAVER ETAL 3,374,766

EXTERNAL PIPE AND TUBE COATING APPARATUS Filed July 25, 1962 F/G. a

IN VENTORS JA CK w 1454 1/5? United States Patent Ofi ice 3,374,766Patented Mar. 26, 1968 3,374,766 EXTERNAL PIPE AND TUBE COATINGAPPARATUS Jack W. Weaver, P.O. Box 1584 74101, and Barney L.

'Weaver, Jr., 5765 E. 30th Place 74114, both of Tulsa,

Okla.

Filed July 25, 1962, Ser. No. 212,401 5 Claims. (Cl. 118-6) Thisinvention pertains to a novel apparatus for applying a coating ofamterial, preferably of a thixotropic material, or the like, includingresinous materials and high solid coatings, to the exterior surface of apipe or tube. Heretofore in applying an exterior coating, other thancementitious materials, to a pipe or tube it has been generallynecessary to use either a spraying technique, pour and wrap, or aspirally movable applicator going continuously around the pipe to wipeon the coating material, such as coal tar products and the like.

Throughout this application it is to be understood that the wordthixotropic material means any material which lowers its viscosity underhigh sheer stress. For example, a container of coal tar epoxy in itsstatic or quiescent condition has high viscosity. Upon adequateagitation of the thixotropic material, its viscosity is loweredsufliciently for application. The present invention employs linearmotion between the pipe and the applicator to provide the necessary highsheer stress in the coating material within the applicator to obtain anoptimum viscosity. A gauge means determines the thickness of the layerof coating material for a given linear velocity of the pipe or workpiece. As the coated pipe emerges from the applicator gauge, eliminationof the high sheer stress restores the coated material to its static orquiescent condition.

In none of the methods available is it possible to actually apply asingle layer of coating material to a surface with said single layer ofcoating material being of the desired thickness. While spraying andwiping methods did put on several layers of coating material in acut'andtry application, there has been no known method of using a singleapplication of a final predetermined thickness other than merelyapplying multiple single applications or filmsor a mass layer which wascontrolled merely by the convolute wiping of the material until theapproximate thickness was reached.

It is therefore an object of the present invention to employ a novelmeans for applying a linear controlled thickness layer of coatingmaterial to the exterior surface of a pipe or tube.

A further object of the invention is to provide a novel means of morerapidly applying a coating material of a predetermined final thicknesslayer in a single application.

Another feature or advantage of the invention is to apply linearly asingle layer of coating material having a more uniform thickness,particularly when utilizing thixotropic materials.

Another advantage or object is to competitively be able to utilize moreexpensive and better coating materials because of the labor savings ofthe overall cost of the job.

A further benefit or advantage is to more readilyapply a thin or a thicklayer utilizing a linear applicator technique with an adjustablethickness gauge to obtain the desired thickness of the coating with onelinear pass of the applicator over the pipe to be coated.

The invention contemplates an elongated sleeve preferably having aflexible portion for example, rubber-like or other expandable material,with said sleeve fitting completely around the pipe to be coated. Thepipe to be coated is positioned relative to the center of the coatingsleeve or applicator to permit relative linear motion between the sleeveand the pipe. The coating material is fed into an enlarged portion ofthe applicator sleeve and as the pipe, for example, moves toward theopposite or smaller diameter or final gauging end of the sleeve, thebulk coating material applied to the pipe is gradually reduced inthickness as the pipe moves, in one form of the invention, until thepipe emerges from the final pneumatic controlled thickness gaugeterminal portion of the sleeve at the desired dimension. The thicknessgauges, in their various variable forms, may be pneumatically adjustableto compensate for variations in application techniques, or compensatedfor changes in viscosity or ambient temperatures, and other variableswhile working the material.

Various advantages, features, or objects of the invention have been setforth, yet it is to be understood that other objects, features andadvantages may become apparent to those skilled in the art. It is to beunderstood that variations, changes, modifications and alterations maybe made in the device as presented herein without departing from thebasic concept of the invention. The form of the invention presentedherein is to be considered as illustrative only and is not to beconsidered as limitations of the invention, as the basic concepts of theinvention may be carried out in many ways, as indicated in the followingspecifications and drawings.

In the drawings:

FIGURE 1 is a side view, partially broken away, showing one form of thesleeve applicator being used in the process of coating a section ofpipe.

FIGURE 2 is a front view of the device substantially as presented alonglines 22 in FIGURE 1, with certain of the apparatus, such as the stand,trough and compressor being omitted for sake of clarity.

FIGURE 3 is a partial end view of a break-open or split type sleevecoupling for over-the-ditch operation.

Referring to the drawings, there is shown in FIGURE 1 a portion of arepresentative section of pipe 20 longitudinally disposed within asleeve or applicator means 30 which applicator is carried longitudinallyor axially of the pipe by a supporting structure 22 having a yokeincluding a base portion 23 and two opposed side portions 24, with eachside portion having a U-shaped journal or hearing 25. A flat annularring 26 preferably made of metal or other rigid material has a pair ofpinions 27 and 28, respectively, secured on opposite sides thereof anddisposed radially to engage their respective U-shaped bearings 25. Theapplicator sleeve is preferably, or at least in the form shown, anelongated flexible envelope or sleeve 3%, which has a larger diameter atthe leading annular end 32 than at the gauge terminal exit end 34 whichhas a terminal peripheral end 38 which is the final portion of theapplicator sleeve which touches the coating as the pipe to be coatedmoves through or relative to the applicator.

A flexible annular flange 40 is secured to the leading annular edge 32and the flexible enlarged portion of the sleeve or applicator means 30end has a radial inner and outer diameter substantially the same as theannular ring 26. The sleeve or applicator means 30 has a tapered portionwhich runs substantially from the annular end 32 to the areasubstantially at point 44 which is an approximate dimension or distancebetween the terminal peripheral end 38 and leading annular end 32. Fromthe point 44 to the terminal end, the present showing represents theflexible sleeve as being basically cylindrical and of the same radialdimensions when in a static condition or when there is no relativemotion between the pipe to be coated and the coating applicator.

The sleeve or applicator means 30 has the terminal peripheral end 38disposed through the annular ring 26 so that the flange 40 is ultimatelyengaged with the annucertain material for coating the outer surface ofpipe of smaller dimensions, generally in the' range of 1 to 3 or 4inches. On pipe running from 4 to 12 inches in the outside diameter, theflexible sleeve material would preferably be of a. greater thickness orless flexible material to maintain its proper or desired shape andcompressional characteristics during operation.

Ordinarily, in the arrangement shown, the supporting structure 22 notonly includes the yoke with the side portions 24 and base portion 23,but a vertically disposed screw 46 which is secured to the base portion23 of the yoke and is threadedly coupled with a stanchion 47 carried ona base 48. Collecting pan 50 is shown merely positioned lower than thesleeve or applicator means 30, but in actual operation thecollecting'pan would preferably be a trough which would be locatedbetween the base portion 23 of the yoke and the annular flange of thesleeve 40. A liquid pump 52 has one end connected by a tube 53 with thepan 50 or trough for collecting or scavenging the residue coatingmaterial and pumping same through the riser pipe 55 which terminates inan outlet 56 to fill the reservoir 58. The outlet from the reservoir 58is controlled by the spigot 60 having a control valve 61 which controlsthe flow of material on to the upper surface of the pipe 20 immediatelyadjacent the leading annular end 32 and the annular flange 40.

As the pipe 20 is moved to the left the coating material will build upon the upper surface thereof and flow down both sides of the pipe bygravity into the lower sleeve reservoir area 63. Upon movement of thepipe to be coated, to the left, as indicated by arrow 64, thethixotropic coating material will be urged from the reservoir coneportion 67 between the normally cylindrical portion' 66 of the sleeve,which is roughly between the terminal peripheral end 38 and the point 44adjacent the cone portion 67 of the sleeve 30 and the pipe, toward theperipheral end 38 of the applicator sleeve 30. After the coatingmaterial flows in an annular layer between the cylindrical portion 66and the rigid pipe, the flexible cylindrical portion 66 ordinarily willbulge outwardly :in annular form from adjacent the apex end of the coneportion 67 to a point farther to the left on the cylindrical portion 66,and tapers down to the inner dimension of the pneumatic or thicknesscontrol 70. The bulge which 7 is represented by a dotted line isindicated by reference numeral 68. This condition takes placesubstantially along the entire sleeve of flexible applicator material upto the gauge 70, and acts as a squeegee eifect to use the resilience ofthe flexible cone to tend to force the coating material out toward thereservoir area 63, while the coating material completely fills the areaof bulge 68.

When in use, and under predetermined conditions with a coating materialof a predetermined viscosity, the coating material will be deposited onthe pipe and as the pipe leaves the terminal end 38 the coating materialremaining on the pipe will be of the desired outside diameter.

Naturally, the characteristics of the flexible sleeve material will beconsidered and will have enough inherent compressional or resistiveforce to compress the coating material to the desired thickness.

While the sleeve or applicator means 30 has definite materialcharacteristics for a particular viscosity and speed of linear motion ofthe application, there are many factors which would cause theseconditions to change. When this is the case, a pressure controllablegauging means is used to establish or determine the ultimate thicknessof the coating material supplied. 7

A coating material thickness gauge control 71) is shown 4 in one form asan'inflatable element which is somewhat oval in cross section, or may besaid to have a flattened circular cross section and is positioned on theoutside of the sleeve within the confines of the terminal peripheralend. A compressor 72 having a pressure gauge 74 is shown coupled to avalve 76 so that the pressure in the thickness gauge control 70 maybevaried to expand or compress the terminal exit end 34 of the sleeve 30per 56 to obtain the desired thickness of final coating material for theparticular operating conditions. In some instances, the thickness gaugecontrol is secured, vulcanized or the like to the outer surface of thesleeve adjacent the terminal end 38 so that the cross-sectional shapeofthe thickness gauge control is pre-established; Naturally, thedimension of the thickness gauge control may be varied since thematerial from whichrit is made is resilient and may yield to bothinternal pressure from the coating ma:

terial and external gauge control pressures. While one thickness gaugecontrol is shown in FIGURE 1, it is to be understood that severalthickness gauge controls generally of the same type as 70 may beemployed side by side on the outside of the sleeve. When this is done,ordinarily the gauges would be employed to provide a greater compressiveforce on the sleeve in definite axial areas so that the gauge meanswould progressively be used to thin out the coating material by thesqueegee action to obtain a better control or more uniform thickness bypermitting the last of the controls to be used to act upon a smallerthickness change. For example, if the job of coating permits a sleeve tobe used without a special thickness gauge control 70, then the endresult of pipe coating thickness is correct for a given relative coatingspeed for the particular viscosity of the coating. Normally, either withor without the use of the thickness gauge control 70, the terminalperipheral end 38 is'in engagement with the outer surface of the pipe tobe coated when there is no relative motion between the applicator andthe pipe. If the coating material to be employed has a high viscosityand would require appreciable pressure for a change of the coatingthickness, then this can be controlled by (1) increasing the pressure inthe pneumatic gauge, (2) increasing the thickness of the sleevematerial, or (3) decreasing the relative speed between the sleeve andthe pipe, or a combination of any of the three methods set forth.

Whilethe thickness gauge 70 has been shown merely as a tubular member,and internal pressure therein determines the thickness of the coatingmaterial, the thickness gauge may have an additional restrictive meansnot necessarily flexible, on the outside thereof so that'the fluidpressure within the thickness gauge may be more eifective under certainconditions. 7

While one form of sleeve or applicator'means is shown as being flexible,it is to be understood that the sleeve may be made also of metal, fiber,or other rigid material and have merely a terminal end sect-ion of 2 to8 inches in axial length which would be of resilient or expandablematerial and of suitable dimensions for receiving a gauge means such as70 or the like. One arrangement of the device has been made with a coneportion 67 of aluminum with the flange also being of aluminum and with asmall cylindrical section extending axially in the area of bulge 68. Aflexible sleeve having a certain resilient characteristic was employedon the terminal end.

While a closed or continuous circular portion of the sleeve is presentedherein, in FIGURE 1, it is to be understood that in over-the-ditchoperations where the pipe may be a line of one or more miles inlength,'without a break therein, a split or break open sleeve (and gaugemeans) may be utilized having edges 84 and 85 substantially parallelwith each other the length of the sleeve, and with an O-ring 86 utilizedin between the edges as shown in FIGURE 3. In one arrangement a flexiblebead also was used along the edge 84 in lieu of the O-ring. With thebreak open type arrangement, a linear projection of rubber 88 was useddown the edge of the split in the sleeve and had clamps 89 pivoted to 90with a tongue portion fitting in a complemental slot 92 for locking thesleeve in place for oVer-the-ditc application. With the latterarrangement the break-open sleeve can be put on or removed anywherealong the pipe. In the latter case, a break-open clamp with adjustmentmeans was used to tighten a band on the outside for compression of theterminal end of the sleeve 38 to act as a removable thickness or gaugecontrol 70.

The gauge control 70 or collar controls the dimension of the outer endof the flexible sleeve which in turn determines the thickness of thematerial applied for a given relative speed and viscosity. The taperedreservoir portion of the sleeve must be full at all times adjacent thecylindrical area and outlet end. The squeegee action of the applicatorwhen in use allows coating material to expand the resilient sleeve sothat the coating material is agitated within the sleeve in a type orkind of linear rolling action to thoroughly wet the pipe surface toachieve an adequate bond of the coating material to the pipe.

It may not be necessary to have the variable collar at the rear end ofthe sleeve at all times in order to maintain the particular coatingthickness. It may be necessary to use the sleeve as is shown without anoutside collar since the rear of the sleeve may be of such dimensions,for certain diameter of pipe that the variable collar would not berequired. The inherent characteristics of the sleeve, per se, would beselected for the uniformity of a particular material having a certainviscosity.

The flexible sleeve basically will flex and slide over the outsidesurface of the pipe, including projections or indentations which varyfrom the nominal dimension of the pipe. The flexible sleeve material maybe made of any suitable flexible substance, for example, urethanematerial has been extensively used as well as natural and syntheticrubbers. Other thermosetting and thermoplastic materials or othermaterial that :will be and are being developed may be satisfactorilyused in the construction of the sleeve. The sleeve may be made of one ofseveral different materials, including flexible plastics, fibers, andthe like. The controlled coating thickness is applied on the pipeWithout runs or sags in the material and is brought about with thisdevice by several features, including the formulation of the material.Certain characteristics are important such as the viscosity of thematerial, the temperature of the coating, the mixture of materials, thesolvent condition of the coating material, if any, and the reaction orsetting time, which is frequently referred to as the curing time. Therelative speed of application of the coating on to the pipe is a factorthat is considered when using the invention. The characteristics of thesleeve facilitate in determining the coating thickness.

The coating thickness is uniform because the gauge end of the flexiblesleeve exerts inward pressure all around the annular layer of coatingmaterial, equally. The equally applied annular pressure on the coatingmaterial uniformly centers the sleeve on the pipe and provides athickness of coating that is uniform. This equally inward annularpressure is important in conjunction with the linearly movable annularlayer applicator, since any variation in the outside diameter of thepipe would alter the pressure accordingly in the pressure gauge means,and accordingly the sleeve on the :high spot area would move outwardlyuntil the pressure, annularly, is balanced. The converse is true for alow spot. Consequently, the inherent characteristics of the device,particularly adjacent the final peripheral edge 38, automatically variesthe coating thickness to compensate for deviation in the surfaceirregularities of the pipe. The uniformity of layer thickness isvirtually constant.

The coating device or apparatus may be used overthe-d-itch, in the yard,or in the shop, in one of the various forms shown.

One form of the invention employs a drive means or feeding arrangementfor feeding lengths or sections of pipe to be coated to the coatingmaterial applicator. Any form of conventional or convenient roller rackor table may be used to align and guide the pipe from a feeding sourceto the pipe support and pipe feeding arrangement. One form representedis shown having a plurality of feed rollers disposed as a part of or ona pipe supporting structure and feeding means, including a base or bases100, with support bars 101 vertically positioned thereon carryingrollers, certain of which may be fee-d rollers 102 positioned to carryor at least friotionally engage the pipe or pipes to be coated and feedsame through the coating material applicator. A drive motor or drivemeans 104 is operatively coupled by drive shafts 103 and 103' to theseveral feed rollers 102 and 102, which feed rollers are merelyrepresentative of a workpiece or pipe carrying and pipe feedingarrangement. Naturally the feed rollers, or guide rollers, or suitableguide means may be employed to adjustably axially align the pipe withthe applicator longitudinal axis by lacing rollers in a Vaform, or anyother conventional method, and may be adjustably movable up or down orleft or right. A speed control is shown connected or coupled to thedrive means 104 for varying or adjustably controlling the rate of feedof the pipe through the applicator by the motor or feed means. Thelinear rate of feed, such as feet per minute of pipe through theapplicator for a given layer thickness, will be determined by thecharacteristics of the coating material employed for the particularcoating job.

The coating material is fed at a controlled rate to the upper surface ofthe pipe so that the coating material will be relatively moved withinthe applicator to be fed to the applicator gauge means for dispositionon the pipe. One or several feed control means for the coating materialmay be appropriately positioned and controlled to regulate the rate offlow of the coating material to the applicator.

While the workpiece feed means is shown as rollers feeding pipe sectionsthrough the applicator, it is to be understood that in long sections ofpipe or pipe line, as in over-the-ditch coating, the pipe would beelevated sufliciently to permit the applicator to be carried by and usedwith a movable cart or truck, and the truck or cart may or may not alsocarry the source of coating material or at least its coupling.

Thixotropic and high solid coating material generally may be any coatingthat can be applied linearly to the external surface of the pipe andafter application thereto will be free from any appreciable drips, runsor sags and the like.

While the applicator means or sleeve is shown as being truncated with anend feed area for admitting the coating material to the applicator, saidapplicator may be fed through an opening in the top thereof and thelarge end of the truncated sleeve may be partially at the lower portionthereof to provide a scavenging trough to be flexibly coupled to feedsame by a pump back to the applicator.

From the foregoing it will be seen that with the invention there will bea faster application of coatings, and the application does notnecessarily depend upon the diameter of the pipe being coated since thisis all considered as being an application, normally of a technicalmaterial that is supplied with one passage of the applicator over thepipe. The invention will apply coatings which are either thin films orthick layers and with or without solvents being employed.

The present showing is by way of illustration only and is not to beconsidered as limitations, since many changes and modifications may bemade herein without departing from the spirit of the subjoined claims.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. An apparatus for applying a coating to the exterior surface of atubular workpiece comprising a sleeve memher adapted to be disposedabout and in substantial engagement with said tubular workpiece andformed of a flexible, imperforate material; said sleeve member having acylindrical body portion including the outlet of said member and aconically configured inlet; means swingably mounting said sleeve memberat the inlet and thereof whereby said member may adapt itself tonon-axially-linear movement of said workpiece; said outlet being formedof an expandable material, a coating material supply associated with theinlet end of said sleeve whereby to apply coating material to saidtubular workpiece; an annulus integral with and co-extensive with theoutlet end of said member; fluid pressure means in communication withsaid annulus to effect uniform pressure and spacing of said outlet andwith respect to an emergent coated portion of said workpiece whereby acoating of uniform and predetermined thickness may be produced.

2. Apparatus as in claim 1 wherein said fluid pressure means isadjustable.

3. Apparatus as in claim 2 including means, independent of said fluidpressure means, whereby to control the thickness of the applied coating.

4. Apparatus as in claim 3 wherein said means which are independent ofsaid pressure means include means to vary the linear speed of theworkpiece being coated.

5. Apparatus as in claim 1 including means to vary the linear speed of aworkpiece passing through said sleeve member whereby to controlthickness of an applied coating independent of said fluid pressuremeans.

References Cited UNITED STATES PATENTS OBrien et al. 118-113 Wilson.Seeley 118-125 Perrault 118-404 Stahl 118-405 X Abbott 118-405 Pharriset al. 118-404 Weekley 118-408 X Dayton 25-38 Gardiner et al. 25-38Wilson 25-38 Robertson 25-38 FOREIGN PATENTS OTHER REFERENCES Germanprinted application 1,105,106, April 1961.

MORRIS KAPLAN, Primary Examiner.

1. AN APPARATUS FOR APPLYING A COATING TO THE EXTERIOR SURFACE OF ATUBULAR WORKPIECE COMPRISING A SLEEVE MEMBER ADAPTED TO BE DISPOSEDABOUT AND IN SUBSTANTIAL ENGAGEMENT WITH SAID TUBULAR WORKPIECE ANDFORMED OF A FLEXIBLE, IMPERFORATE MATERIAL; SAID SLEEVE MEMBER HAVING ACYLINDRICAL BODY PORTION INCLUDING THE OUTLET OF SAID MEMBER AND ACONICALLY CONFIGURED INLET; MEANS SWINGABLY MOUNTING SAID SLEEVE MEMBERAT THE INLET AN THEREOF WHEREBY SAID MEMBER MAY ADAPT ITSELF TONON-AXIALLY-LINEAR MOVEMENT OF SAID WORKPIECE; SAID OUTLET BEING FORMEDOF AN EXPANDABLE MATERIAL, A COATING MATERIAL SUPPLY ASSOCIATED WITH THEINLET END OF SAID SLEEVE WHEREBY TO APPLY COATING MATERIAL TO SAIDTUBULAR WORKPIECE; AN ANNULUS INTEGRAL WITH AND CO-EXTENSIVE WITH THEOUTLET END OF SAID MEMBER; FLUID PRESSURE MEANS IN COMMUNICATION WITHSAID ANNULUS TO EFFECT UNIFORM PRESSURE AND SPACING OF SAID OUTLET ANDWITH RESPECT TO AN EMERGENT COATED PORTION OF SAID WORKPIECE WHEREBY ACOATING OF UNIFORM AND PREDETERMINED THICKNESS MAY BE PRODUCED.